Coil former for a transformer

ABSTRACT

A coil former for a transformer having four flanges which are consecutively arranged on a central part, each of the two intermediate flanges having a thick edge in which a connection pin is connected. The two thick edges are diametrically arranged on opposite sides of the central part.

United States Patent [1 1 DeJong et al.

[4 1 Jan. 22, 1974 COIL FORMER FOR A TRANSFORMER Inventors: Nicolaas Johannes DeJong; Mannes Arie, both of Middelkamp, Emmasingel, Eindhoven, Netherlands U. S. Philips Corporation, New York, NY.

Filed: Mar. 16, 1973 Appl. N0.: 341,984

Assignee:

Foreign Application Priority Data Mar. 22, 1972 Netherlands 7203795 US. Cl. 336/192, 336/208 Int. Cl H01f 15/10, HOlf 27/30 Field of Search 336/192, 198, 208

[56] References Cited 1 UNITED STATES PATENTS 3,189,707 6/1965 Norden et al 336/198 X 2,594,915 4/1952 Guillemant 336/208 X Primary ExaminerThomas J. Kozma Attorney, Agent, or Firm-Frank R. Trifari [5 7] ABSTRACT A coil former for a transformer having four flanges which are consecutively arranged on a central part, each of the two intermediate flanges having a thick edge in which a connection pin is connected. The two thick edges are diametrically arranged on opposite sides of the central part.

4 Claims, 2 Drawing Figures 1 COIL FORMER FOR A TRANSFORMER The invention relates to a coil former for a transformer, consisting of a central .part on which a first winding space is bounded by a first flange which is arranged near one end of the central part, and by a second flange which is arranged between this end and the middle of the central part, a second winding space being bounded by a third flange which is arranged near the other end of the central part and by a fourth flange which is arranged between this other end and the middle of the central part, a third winding space being present between the second and the fourth flange.

Coil formers of this kind can be used for the manufacture of transforemrs where, for example, a primary winding is provided in the third winding space, and two I secondary windings in the first and the second winding space, respectively, the latter winding spaces preferably having the same'dimensions. These windings can be connected to connection pins which are preferably provided in the sides of the flanges so as to save space. However, for the provision of the connection pins it is necessary that the relevant flange edges have a given minimum thickness which is usually larger than the optimum thickness of the flanges themselves. For the first and the third flange, arranged at the ends of the central part, this usually does not impose problems because near these ends there is usually sufficient space to make the flange edges thicker than the flanges themselves, without the winding space being reduced. However, for the second and the fourth flange the problem arises that a thickened flange edge always locally shortens a winding space, which gives rise to problems when the winding is fitted because now this winding space does not have the same length everywhere. One of the two flanges bounding the third winding space could be given the thickness required for the provision of the connection pins over its entireyvidth, so that the winding spaces have the same length over their centre width, but this has the drawback that the coupling between the two windings on each side of the relevant flange deteriorates, which is not acceptable in many cases. Moreover, the transformer then becomes asymmetrical, unless the other flange bounding the third winding space is also given the same thickness, so that the coupling between the two windings on each side of this flange also deteriorates, which is of course not acceptable either.

The invention has for its object to provide a coil former which is provided with connection pins, but which does not have the described drawbacks. To this end, the coil former according to the invention is characterized in that one of the edges of the second as well as the fourth flange is made to be thicker than the opposite edge, the thick edges of the second and the fourth flange being situated on diametrically opposed sides of the central part, the thick edges accommodating connection pins for a transformer winding to be provided on the coil former.

This enables a symmetrical construction of the coil former, whilst the thickness of the second and the fourth flange is so small over a substantial part of the width of these flanges that proper coupling exists between the windings situated on both sides of these flanges.

The construction of the coil former according to the invention is simplest and the'provision of the windings is easiest if the sides of the second and the fourth flange, facing the first and the second winding space, respectively, are perpendicular to the axis of the central part, whilst the sides of these flanges which face the third winding space enclose, at least over a substantial part of their width, an angle other than with the said axis and are parallel to each other.

For a transformer comprising a first, a second and a third winding, the said windings being arranged in the first, the second and the third winding space, respectively, of a coil former according to the invention, the said windings are preferably arranged such that the transformer is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides said axis into two equal pieces. That is to say, the first and the second winding are identical as regards their dimensions and number of turns, whilst the third winding is divided into two equal pieces by the said plane in view of its location in the third winding space.

The invention will be described in detail with reference to the drawing.

FIG. 1 is a plan view of a coil former according to the invention, and

FIG. 2 is a side elevation of a transformer incorporating the coil former shown in FIG. 1.

The coil former shown in FIG. 1 is made of an insulating synthetic resin material and consists of a preferably cylindrical central part 1, on which a first winding space 3 is situated which is bounded by a first flange 5 which is arranged near one end (the left-hand end in FIG. 1) of the central part and by a second flange 7 which is arranged between this end and the middle of the central part. A second winding space 9 is bounded by a third flange 11 which is arranged near the other end (the right-hand end in FIG. 1) of the central part 1 and by a fourth flange 13 which is arranged between this right-hand end and the middle of the central part. A third winding space 15 is present between the second flange 7 and the fourth flange 13.

As is shown in FIG. 1, the side of the second flange 7 which faces the first winding space 3 is perpendicular to the axis of the central part 1, like the side of the fourth flange 13 which faces the second winding space 9. The sides of these two flanges which face the third winding space 15, however, enclose an angle which is not 90 with the said axis over the largest part of their width. These sides are parallel to each other, so that the third winding space has a constant length over the major part of its width. As a result of the described position of the sides of the flanges 7 and 13, these flanges are approximately wedge-shaped. The second flange 7, consequently, has an edge 17 which is substantially thicker than the oppositely arranged edge 18, and the fourth flange 13 also has an edge 19 which is substantially thicker than the oppositely arranged edge 20.

As appears from FIG. 1, the thick edges 17 and 19 are situated on diametrically opposed sides of the central part 1.

Provided in the thick edges 17 and 19 of the flanges 7 and 13 are connection pins 21 which are preferably embedded in the synthetic resin material of the coil former, their length exceeding the height of the flanges so that they project above as well as below the coil former (see also FIG. 2).

The first flange 5 and the third flange 11 are provided, on both sides of the central part 1, with thick 3 side edges 23 and 25, respectively, in which connection pins 21 are provided in the same manner.

FIG. 2 shows a transformer which is manufactured by means of the coil former shown in FIG. 1. In the first winding space 3, a first winding 27 is provided, in the second winding space 9 a second winding 29, and in the third winding space a third winding 31. Each of these windings terminates in two connection wires 33 which are connected, for example, by soldering, to the upper ends of the connection pins 21. The lower ends of these connection pins can be soldered, for example, in a printed circuit board.

If desired, the transformer also comprises a ferromagnetic core which is not shown in this figure for the sake of simplicity.

The first winding 27 and the second winding 29 are made of the same number of turns of copper wire of the same thickness, so that they are fully identical because the dimensions of the first and the second winding space, 3 and 9, are also equal. The third winding 31 can consist of a different number of turns of copper wire having a different thickness. Due to the location of the third winding space 15 and the shape of the flange 7 and 13, this winding is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides this axis into two equal parts. Due to this fact and the fact that the first and the second winding 7 and 29 are identical, the entire transformer has the same symmetry.

The described embodiment of a coil former according to the invention is a particularly simple one. However, it will be obvious that the imposed requirements can also be satisfied within the scope of the invention by other embodiments. For example, the sides of the flanges 7 and 13 which face the third winding space 15 can also be perpendicular to the axis of the central part 1, whilst the sides of the first flange 5 and the second flange 7 which face the first winding space 3 deviate from the perpendicular position, like the sides of the third flange 11 and the fourth flange 13 which face the second winding space 9. In that case, the first and the second winding space 3 and 9 are inclined with respect to the axis of the central part 1.

What is claimed is:

1. A coil former for a transformer comprising a central part on which a first winding space is bounded by a first flange which is arranged near one end of the central part and by a second flange which is arranged between said one end and the middle of the central part, a second winding space being bounded by a third flange which is arranged nearthe other end of the central part and by a fourth flange which is arranged between said other end and the middle of the central part, a third winding space being present between the second and the fourth flanges, one of the edges of the second and the fourth flanges being made to be thicker than the opposite edges thereof, the thick edges of the second and the fourth flanges being situated on diametrically opposed sides of the central part with, the thick edges accommodating connection pins for a transformer winding to be provided on the coil former.

2. A coil former as claimed in claim 1, characterized in that the sides of the second and the fourth flanges which face the first and the second winding spaces, respectively, are perpendicular to the axis of the central part, and, the sides of said second and fourth flanges which face the third winding space form, at least over a substantial part of their width, an angle other than with the said axis and are parallel to each other.

3. A transformer coil form as claimed in claim 1 further comprising a first, a second and a third winding which are arranged in the first, the second and the third winding spaces, respectively, of the coil former to form a transformer, characterized in that the said windings are arranged such that the transformer is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides this axis into two equal parts.

4. A transformer coil form as claimed in claim 2 further comprising a first, a second and a third winding which are arranged in the first, the second and the third winding spaces, respectively, of the coil former to form a transformer, characterized in that the said windings are arranged such that the transformer is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides this axis into equal parts. 

1. A coil former for a transformer comprising a central part on which a first winding space is bounded by a first flange which is arranged near one end of the central part and by a second flange which is arranged between said one end and the middle of the central part, a second winding space being bounded by a third flange which is arranged near the other end of the central part and by a fourth flange which is arranged between said other end and the middle of the central part, a third winding space being present between the second and the fourth flanges, one of the edges of the second and the fourth flanges being made to be thicker than the opposite edges thereof, the thick edges of the second and the fourth flanges being situated on diametrically opposed sides of the central part with, the thick edges accommodating connection pins for a transformer winding to be provided on the coil former.
 2. A coil former as claimed in claim 1, characterized in that the sides of the second and the fourth flanges which face the first and the second winding spaces, respectively, are perpendicular to the axis of the central part, and, the sides of said second and fourth flanges which face the third winding space form, at least over a substantial part of their width, an angle other than 90* with the said axis and are parallel to each other.
 3. A transformer coil form as claimed in claim 1 further comprising a first, a second and a third winding which are arranged in the first, the second and the third winding spaces, respectively, of the coil former to form a transformer, characterized in that the said windings are arranged such that the transformer is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides this axis into two equal parts.
 4. A transformer coil form as claimed in claim 2 further comprising a first, a second and a third winding which are arranged in the first, the second and the third winding spaces, respectively, of the coil former to form a transformer, characterized in that tHe said windings are arranged such that the transformer is symmetrical with respect to a plane which is perpendicular to the axis of the central part and which divides this axis into equal parts. 